Add a MCTargetStreamer interface.

This patch fixes an old FIXME by creating a MCTargetStreamer interface
and moving the target specific functions for ARM, Mips and PPC to it.

The ARM streamer is still declared in a common place because it is
used from lib/CodeGen/ARMException.cpp, but the Mips and PPC are
completely hidden in the corresponding Target directories.

I will send an email to llvmdev with instructions on how to use this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192181 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfException.h b/lib/CodeGen/AsmPrinter/DwarfException.h
index 49a85d8..1575161 100644
--- a/lib/CodeGen/AsmPrinter/DwarfException.h
+++ b/lib/CodeGen/AsmPrinter/DwarfException.h
@@ -29,6 +29,7 @@
 class MCExpr;
 class MCSymbol;
 class Function;
+class ARMTargetStreamer;
 class AsmPrinter;
 
 //===----------------------------------------------------------------------===//
@@ -177,6 +178,8 @@
 
 class ARMException : public DwarfException {
   void EmitTypeInfos(unsigned TTypeEncoding);
+  ARMTargetStreamer &getTargetStreamer();
+
 public:
   //===--------------------------------------------------------------------===//
   // Main entry points.